Michael Jacobs twice gave the home side the lead, but Shrewsbury hit back quickly on both occasions.
After David Davies and James Collins had twice restored parity, Jon Taylor rifled home an 18-yard half-volley to break Cobblers hearts with three minutes to play.
"When their first goal went in, I wondered what I'd done wrong because it was such a special goal," Turner said. "It was good to get back on level terms so soon but their second goal was even better than the first one.
"But we kept going and I was pleased with the way we responded after the midweek defeat to Bury.
"It was a great win for us and keeps us nicely up there."
Source: PA
Source: PA